<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .munes {
            width: 300px;
            height: 500px;
            border: 1px solid red;
            margin-left: auto;
            margin-right: auto;
        }
        .munes.header {
            width: 300px;
            height: 50px;
            border: 1px solid red;
        }
        .munes.content {
            width: 300px;
            height: 400px;
        }
    </style>
</head>
<body>
<div class="munes">
    <div class="header" onclick="myfunction()">菜单</div>
    <div class="content">内容</div>
</div>

<script type="text/javascript">
    function myfunction()
    {
    alert("你点击了菜单");
    }

</script>

</body>
</html>